This PR implements the following changes.

• Fixes the styling of the breadcrumb links in the File history page.
• Fixes the broken links in the breadcrumb that are more than one level deep. For example, in https://pagure.io/pagure/history/doc/usage/troubleshooting.rst, clicking on the usage link in the breadcrumb opens a page with the Page not found (404) error.
• Changes the name of the file in the breadcrumb of the File history page to a link to the file. This fixes https://pagure.io/pagure/issue/4793.
• Simplifies the breadcrumb item generation code since the output_type is hardcoded to "history" in the view that uses the file_history.html template.

Testing instructions:

• Check out the source branch of this PR in the local Pagure development environment.
• Open a file that is multiple-levels deep inside a repository.
• Open the history page of the file.
• Check and verify that the breadcrumb links properly spaced and separated by /.
• Verify that the links to the folders and/or files more than one level deep point to the correct pages and that no 404 error is seen when opening those links.
• Verify that the file name in the breadcrumb of the File history page is a link to the file in the corresponding branch.